KR20080088494A - Radio base station apparatus, resource allocation method and resource allocation program - Google Patents

Abstract

A wireless base station, a method for allocating resources, and a program for allocating resources are provided to prevent a drop in the throughput of a wireless base station by enabling a UE(User Equipment) to appropriately receive data from the wireless base station in order to minimize the transmission of NACK(Negative Acknowledgement) information to the wireless base station and the retransmission of data to the UE. A wireless base station, which allocates resources to an HS-PDSCH(High Speed Physical Downlink Shared Channel) and transmits data to a UE through the HS-PDSCH, comprises a BLER(Block Error Rate) measurement part(14) and a resource allocation part(16). The BLER measurement part measures the BLER of a signal received from the UE. When the measured BLER is larger than a target value, the resource allocation part gradually increases the amount of data transmission power which is allocated to the HS-PDSCH as a resource.

Description

Wireless base station device, resource allocation method and resource allocation program {RADIO BASE STATION APPARATUS, RESOURCE ALLOCATION METHOD AND RESOURCE ALLOCATION PROGRAM}

This application claims its priority based on Japanese Patent Application No. 2007-084463, filed March 28, 2007, the disclosure of which is incorporated herein by reference.

The present invention relates to a technique for allocating resources to a High Speed Physical Downlink Shared Channel (HS-PDSCH) used for transmitting data to a mobile station in a wireless base station apparatus.

The third-generation partnership project (3GPP) defines the specification of High Speed Downlink Packet Access (HSDPA).

According to the HSDPA, the wireless base station apparatus transmits data to a user equipment (UE) via the HS-PDSCH.

In addition, according to HSDPA, as an index indicating downlink transmission quality, a CQI (Channel Quality Indicator) calculated by the UE is used. This CQI is reported to the radio base station apparatus through the High Speed Dedicated Physical Control Channel (HS-DPCCH), and the radio base station apparatus is based on the CQI reported from the UE to allocate resource allocation for the HS-PDSCH. For example, see Japanese Patent Laid-Open No. 2006-217190.

On the other hand, 3GPP TS25.141 allows an error range of ± 2 dB for the CQI reported from the UE to the radio base station apparatus.

Therefore, when the radio base station apparatus directly uses the value of the CQI reported to the UE, proper resource allocation cannot be performed. Therefore, the UE side cannot properly receive data from the radio base station apparatus, resulting in a decrease in throughput in the radio base station apparatus.

An object of the present invention is to provide a radio base station apparatus, a resource allocation method, and a resource allocation program capable of preventing a decrease in throughput.

In order to achieve the above object, according to the present invention, a radio base station apparatus for allocating resources to the HS-PDSCH and transmitting data to the mobile station through the HS-PDSCH,

A BLER measurement unit for measuring a BLER of a signal received from a mobile station; And

If the measured BLER is equal to or greater than the target value, the resource allocating unit for incrementally increasing the data transmission power allocated to the HS-PDSCH as a resource by a predetermined amount.

Provided is a wireless base station apparatus comprising a.

In order to achieve the above object, according to the present invention, there is provided a resource allocation method used by a radio base station apparatus for allocating a resource to an HS-PDSCH and transmitting data to a mobile station through the HS-PDSCH.

Causing the wireless base station apparatus to measure the BLER of the signal received from the mobile station; And

If the measured BLER is greater than or equal to the target value, causing the radio base station apparatus to incrementally increase the data transmission power allocated to the HS-PDSCH as a resource by a predetermined amount;

There is provided a method comprising a.

To achieve the above object, according to the present invention, there is provided a resource allocation program for causing a computer to act as a radio base station apparatus for allocating resources to the HS-PDSCH and transmitting data to the mobile station via the HS-PDSCH.

Measuring the BLER of the signal received from the mobile station; And

If the measured BLER is greater than or equal to the target value, a step of incrementally increasing the data transmission power allocated to the HS-PDSCH as a resource by a predetermined amount

A resource allocation program for executing the is provided.

According to the present invention, when the measured BLER is greater than or equal to the target value, the radio base station apparatus increases the transmission power allocated to the HS-PDSCH.

Therefore, the mobile station side can properly receive data from the radio base station apparatus, so that the number of transmissions of NACK information to the radio base station apparatus is minimized. Therefore, the number of times of data retransmission from the radio base station apparatus to the mobile station in the MAC-hs layer can be reduced, so that a decrease in throughput in the radio base station apparatus can be prevented.

The foregoing and other objects, features, and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings which illustrate examples of the present invention.

Preferred embodiments of the present invention will be described below with reference to the drawings.

1 exemplarily illustrates a communication technique performed between a wireless base station apparatus 10 and a UE (mobile station) 20 according to an exemplary embodiment.

Referring to FIG. 1, in the downlink, the radio base station apparatus 10 transmits data to the UE 20 via the HS-PDSCH.

In the uplink, the UE 20 receives an acknowledgment (ACK) / NACK (indication) indicating whether or not data is properly received from the above-described CQI or the radio base station apparatus 10 to the radio base station apparatus 10 via the HS-DPCCH. Negative ACK) information is transmitted.

2 is a block diagram showing an internal configuration of the radio base station apparatus 10. As shown in FIG. 2 shows only the part which concerns on this invention, and abbreviate | omits other part.

Referring to FIG. 2, the radio base station apparatus 10 includes an HS-DPCCH decoder 11, a CQI obtainer 12, an ACK / NACK acquirer 13, a BLER measurer 14, and a scheduling determiner 15. And a resource allocation unit 16.

The HS-DPCCH decoder 11 decodes a signal received through the HS-DPCCH from the UE 20.

The CQI obtaining unit 12 obtains the CQI included in the received signal decoded by the HS-DPCCH decoder 11.

The ACK / NACK acquisition unit 13 obtains ACK / NACK information included in the received signal decoded by the HS-DPCCH decoder 11.

The BLER measurement unit 14 measures the BLER of the signal received from the UE 20 through the HS-DPCCH.

The scheduling determiner 15 performs scheduling for the UE 20 to which the resource allocator 16 allocates resources. For example, when the UE 20 starts the HSDPA service, the scheduling determination unit 15 determines execution of resource allocation for the UE 20.

When the scheduling determination unit 15 determines the execution of resource allocation for the UE 20, the resource allocation unit 16 is based on the CQI obtained by the CQI obtaining unit 12, and as a resource, data transmission power, The data TBS (Transport Block Size), data modulation scheme, and the number of data codes used in the HS-PDSCH are allocated. In this case, the resource allocated to the HS-PDSCH can be calculated by any method. For example, a method for calculating the transmit power allocated to the HS-PDSCH, which is described in 3GPP TS25.214, "Primary-CPICH corresponding to the main-CPICH + measured power offset in the cell + received CQI. One way is to use the formula in the cell + Measurement Power Offset + Reference Power Offset corresponding to the received CQI).

In addition, when the BLER measured by the BLER measurement unit 14 is equal to or larger than the target BLER which is the target value of the BLER, the resource hill party unit 16 allocates the resource to the HS-PDSCH. That is, the transmission power allocated to the HS-PDSCH is increased in steps by a predetermined amount.

Here, in the radio base station apparatus 10, in consideration of the error of the CQI reported from the UE 20, an upper limit (for example, 2 dB) for an increased amount of transmission power allocated to the HS-PDSCH is determined.

Even if the amount of increased transmission power reaches the upper limit, it is also possible that the measured BLER is greater than or equal to the target BLER as a result of the resource allocation unit 16 for increasing the transmission power allocated to the HS-PDSCH. In this case, the resource allocation unit 16 determines that the error of the CQI has exceeded the allowable level, and changes other resources (TBS, modulation scheme, number of codes) other than the transmission power allocated to the HS-PDSCH. .

 The HS-DPCCH transmitter (not shown) transmits data to the UE 20 via the HS-PDSCH to which resources are allocated by the resource allocating unit 16.

Resource allocation operation by the wireless base station apparatus 10 will be described below. Here, assuming that resources have been allocated to the HS-PDSCH since the UE 20 has started the HSDPA service, the subsequent operation will be described.

FIG. 3 is a flowchart exemplarily showing the operation of the radio base station apparatus 10 that changes the transmission power allocated to the HS-PDSCH, and FIG. 4 shows an increased amount of the transmission power allocated to the HS-PDSCH. It is a flowchart showing the operation of the radio base station apparatus 10, which changes the other resources allocated to the HS-PDSCH when exceeded.

In Figures 3 and 4, the following coefficients are used.

i: number of steps when the transmission power allocated to the HS-PDSCH changes step by step

r: increased amount of transmit power allocated to units corresponding to the number of steps i

j: the number of steps when other resources allocated to the HS-PDSCH change step by step

T: length of time the BLER is measured

Qmax: upper limit of the increased amount of transmit power allocated to the HS-PDSCH

Pmax: upper limit of transmit power that can be allocated to the HS-PDSCH

Here, r, Qmax and the target BLER are stored in advance in the resource allocating unit 16 or specified in the resource allocating unit 16 from the outside. T is stored in advance in the BLER measuring section 14 or is designated to the BLER measuring section 14 from the outside.

Referring to FIG. 3, first, in step 1-1, the resource allocator 16 initializes the number of steps i (i = 0). In addition, the BLER measuring unit 14 measures the BLER of the received signal during T.

Subsequently, in step 1-2, the resource allocation unit 16 compares the measured BLER obtained in step 1-1 with the target BLER. If the measured BLER is greater than or equal to the target BLER, the operation proceeds to step 1-3. On the other hand, if the measured BLER is less than the target BLER, the operation proceeds to steps 1-7.

In step 1-3, the resource allocation unit 16 compares the increased amount of transmission power allocated to the HS-PDSCH with an upper limit Qmax. Here, the increased amount of transmit power is represented by r × i. If the increased amount of the transmission power exceeds Qmax, the resource allocation unit 16 determines that the error of the CQI has exceeded the allowable level, and the operation proceeds to step 2-1 of FIG. On the other hand, if the increased amount of transmit power is equal to or less than Qmax, the operation proceeds to step 1-4.

In steps 1-4, the resource allocation unit 16 increments the number of steps i by one. Subsequently, in step 1-5, the resource allocation unit 16 increases the transmission power actually allocated to the HS-PDSCH by r × i.

Subsequently, in steps 1-6, the resource allocator 16 assigns the transmission power (including the increased amount in steps 1-5) actually allocated to the HS-PDSCH of the transmission power that can be allocated to the HS-PDSCH. Compare with upper limit Pmax. Here, Pmax is determined by considering other channels. If the transmit power is less than or equal to Pmax, the operation proceeds to step 1-7. On the other hand, if the transmit power exceeds Pmax, the operation proceeds to steps 1-8.

In steps 1-8, the resource allocator 16 reduces the transmission power allocated to the HS-PDSCH to Pmax, and the number of other resources (TBS, codes) in the 3GPP TS25.141 table by the amount corresponding to the decrease. , The modulation scheme), and the operation proceeds to steps 1-7. For example, if the reduced amount of transmit power is 2 dB, the number of TBS or codes is increased by an amount corresponding to 2 dB, or a change is made in the modulation scheme to compensate for the amount corresponding to 2 dB. Here, the number of TBSs, modulation schemes and codes need not all be changed (it is sufficient if at least one of them (TBS, modulation scheme, number of codes) changes).

In step 1-7, the BLER measuring unit 14 measures the BLER of the received signal for T, after which the operation returns to step 1-2.

Referring to FIG. 4, when the increased amount of transmit power allocated to the HS-PDSCH exceeds Qmax in step 1-3 of FIG. 3, first, in step 2-1, the resource allocator 16 ) Initializes the number j of steps. In this case, since the measured BLER is greater than or equal to the target BLER, the operation starts by setting the number j of steps to one.

Subsequently, in step 2-2, the resource allocation unit 16 changes other resources (TBS, modulation scheme, number of codes) other than the transmission power allocated to the HS-PDSCH. In this case, the increased amount of transmit power remains unchanged, while the other resources (TBS, modulation scheme, number of codes) vary with the offset corresponding to j applied to other resources in the 3GPP TS25.141 table. . For example, the number of TBSs or codes is reduced by an amount corresponding to j, or a change occurs in the modulation scheme in response to j. Here, the number of TBSs, modulation schemes and codes need not all be changed (it is sufficient if at least one of them (TBS, modulation scheme, number of codes) changes).

Subsequently, in step 2-3, the BLER measuring unit 14 measures the BLER of the received signal during T. Subsequently, in step 2-4, the resource allocation unit 16 compares the measured BLER obtained in step 2-3 with the target BLER. If the measured BLER is greater than or equal to the target BLER, the operation proceeds to step 2-5. On the other hand, if the measured BLER is less than the target BLER, the operation returns to step 2-3.

In step 2-5, the resource allocation unit 16 increments the number j of steps one by one, and the operation returns to step 2-2.

As described above, according to the present exemplary embodiment, when the measured BLER is greater than or equal to the target BLER, the radio base station apparatus 10 increases the transmission power allocated to the HS-PDSCH.

Subsequently, the UE 20 side can properly receive data from the radio base station apparatus 10, so that the number of transmissions of NACK information for the radio base station apparatus 10 is minimized. Thus, the number of data transmissions from the radio base station apparatus 10 to the UE 20 in the MAC-hs layer can be reduced, so that a decrease in throughput in the radio base station apparatus 10 can be prevented.

In addition, according to the present exemplary embodiment, in consideration of the error of the CQI, an upper limit for an increased amount of transmission power is determined by the radio base station apparatus 10. Also, if the measured BLER is still more than the target BLER even after the increased amount of transmission power reaches the upper limit, the radio base station apparatus 10 determines that the error of the CQI exceeds the allowable level, and the other allocated to the HS-PDSCH. Change the transmit power.

Subsequently, even when the UE 20 reports that the CQI has been exceeded too high relative to the allowable level of the error of the CQI, the radio base station apparatus 10 may perform resource allocation within an appropriate range, and thus the radio base station apparatus 10 Allow the prevention of a decrease in throughput.

Although the wireless base station apparatus 10 is implemented by using the dedicated hardware described above, it also records a program to implement such a function on a computer readable recording medium and causes the computer to read and execute a program recorded on the recording medium. It may be noted that the present invention may be implemented by acting as a radio base station apparatus 10 for performing the same. Computer-readable recording media include recording media such as floppy disks, magneto-optical disks or CD-ROMs, and storage devices such as hard disk devices built into a computer. In addition, a computer-readable recording medium may be a predetermined time, such as a medium (transmission medium or a transmission wave) that dynamically holds a program for a short time, such as when the program is transmitted through the Internet, and a volatile memory in a computer. It includes a medium holding a program.

Although the invention has been shown and described in particular in connection with exemplary embodiments of the invention, the invention is not limited to these embodiments. Those skilled in the art will appreciate that changes may be made in various forms and details without departing from the spirit and scope of the invention as defined by the claims.

1 illustratively illustrates a communication technique performed between a wireless base station apparatus and a UE in accordance with an exemplary embodiment of the present invention;

FIG. 2 is a block diagram showing an internal configuration of the wireless base station apparatus shown in FIG. 1;

3 is a flowchart illustratively showing the operation of the wireless base station apparatus shown in FIG. 1, varying the transmit power allocated to the HS-PDSCH; And

FIG. 4 exemplarily illustrates the operation of the wireless base station apparatus shown in FIG. 1 that changes another resource allocated to the HS-PDSCH when the increased amount of transmit power allocated to the HS-PDSCH exceeds an upper limit. Flowchart.

Claims (10)

A radio base station apparatus for allocating resources to an HS-PDSCH and transmitting data to a mobile station through the HS-PDSCH. A BLER measurement unit for measuring a BLER of a signal received from the mobile station; And If the measured BLER is equal to or larger than a target value, a resource allocation unit for incrementally increasing the amount of data transmission power allocated to the HS-PDSCH as the resource by a predetermined amount. Wireless base station device comprising a. The resource allocating unit according to claim 1, wherein if the measured BLER is equal to or greater than the target value after the increased amount of the transmission power allocated to the HS-PDSCH reaches its upper limit, the resource allocation unit is assigned to the HS-PDSCH. A wireless base station apparatus for changing a resource other than the amount of transmit power. The radio base station apparatus according to claim 2, wherein the resource allocation unit reduces the data TBS allocated to the HS-PDSCH as the other resource. The radio base station apparatus according to claim 2, wherein the resource allocator reduces the number of data codes allocated to the HS-PDSCH as the other resource. The radio base station apparatus according to claim 2, wherein the resource allocating unit changes a data modulation scheme allocated to the HS-PDSCH as the other resource. A resource allocation method used by a radio base station apparatus for allocating resources to an HS-PDSCH and transmitting data to a mobile station through the HS-PDSCH, Causing the wireless base station apparatus to measure the BLER of a signal received from the mobile station; And If the measured BLER is equal to or greater than a target value, causing the radio base station apparatus to incrementally increase the amount of data transmission power allocated to the HS-PDSCH as the resource by a predetermined amount; Resource allocation method comprising a. The amount of transmit power allocated to the HS-PDSCH if the measured BLER is greater than or equal to the target value after the increased amount of the transmit power allocated to the HS-PDSCH reaches its upper limit. The method of allocating resources further comprises changing other resources. 8. The method of claim 7, wherein, in the other resource allocation, the TBS allocated to the HS-PDSCH as the other resource is reduced. 8. The method of claim 7, wherein, in the other resource allocation, the number of data codes allocated to the HS-PDSCH as the other resource is reduced. 8. The method of claim 7, wherein, in the other resource allocation, the data modulation scheme allocated to the HS-PDSCH as the other resource is changed.

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